1. Field of the Invention
This invention relates to a ventilating system for use with protective clothing of the type including a head enclosure and more particularly to the provision in such a system of a flow of air to the limbs.
2. Prior Art
Health and safety considerations dictate that persons working in atmospheres contaminated with airborne substances of a hazardous nature wear a head enclosing hood, the interior of which is supplied with a positive pressure plenum of pure air for respiration therein. Regardless of the temperature of the atmosphere, the rest of the person's body must at least be clothed with normal working or street wear. However, many working atmospheres are contaminated with airborne substances which are hazardous not just from breathing of the atmosphere, but also from skin contact therewith. Under these conditions, it is desirable that protective clothing be worn which includes not just a head enclosing hood, but which also includes various outer coverings which substantially enclose a person's body so that no skin is exposed. Protective clothing may be relatively specialized, but it frequently includes both inner garments and an outer coverall. Gloves and boots are usually connected to the inner or outer coveralls. The outer coveralls are frequently designed to be disposable after use.
The outer and inner coveralls such as described above may be made of woven or knitted fabric. Fabric resists tearing, punctures and the like when the user is working. Fabric also permits a reasonable amount of perspirative evaporation therethrough. Nevertheless, a person working with such protective clothing tends to become quite warm. Further, there exists some risk of contact with airborne contaminants, as airborne contaminants may enter the body covering at the extremities of the user's limbs or pass through the outer coveralls, proceed through the inner coveralls, and contact the user's skin. Outer coveralls may also be made of relatively light-weight, non-porous material. However, such non-porous materials become very warm under working conditions and there exists some risk of contact with airborne contaminants entering the body covering at the extremities of the user's limbs.
It is an object of this invention to provide an air flow to a user's limbs for ventilation of an outer body covering, the ventilation cooling the user's body by flowing about the extremities thereof and tending to exert a slight positive pressure interior of the outer covering to prevent the entry of contaminants therein.
It is a further object of the present invention that such ventilation be provided while attenuating the sound thereof.
It is yet another object of the present invention that such ventilation be part of an air delivery system which delivers air to a user's head enclosure, the head enclosure receiving pressurized air within a predetermined range of air volume per unit time regardless of the conditions under which the user's body is being ventilated.